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Kirk McKusick d7770a5495 Eliminate snaplk / bufwait LOR when creating UFS snapshots
Each vnode has an embedded lock that controls access to its contents.
However vnodes describing a UFS snapshot all share a single snapshot
lock to coordinate their access and update. As part of creating a
new UFS snapshot, it has to have its individual vnode lock replaced
with the filesystem's snapshot lock.

The lock order for regular vnodes with respect to buffer locks is that
they must first acquire the vnode lock, then a buffer lock. The order
for the snapshot lock is reversed: a buffer lock must be acquired before
the snapshot lock.

When creating a new snapshot, the snapshot file must retain its vnode
lock until it has allocated all the blocks that it needs before
switching to the snapshot lock. This update moves one final piece of
the initial snapshot block allocation so that it is done before the
newly created snapshot is switched to use the snapshot lock.

Reported by:  Witness code
MFC after:    1 week
Sponsored by: Netflix
2021-09-18 17:02:30 -07:00
.cirrus-ci Cirrus-CI: add some timing info on pkg install failure 2021-08-04 15:02:00 -04:00
.github [skip ci] fix syntax in CODEOWNERS 2021-07-22 10:58:54 -06:00
bin sh: improve emacs mode 2021-08-28 16:11:57 +02:00
cddl dtrace.1: Document a couple of preprocessor-related options 2021-09-07 14:04:50 -04:00
contrib readelf: document that -u / --unwind is not yet implemented 2021-09-17 10:22:05 -04:00
crypto openssh: use global state for blacklist in grace_alarm_handler 2021-09-16 14:10:11 -04:00
etc Add support for jail.conf.d 2021-09-10 00:30:04 -05:00
gnu dialog: fix macro redefinition 2021-03-01 16:01:44 +01:00
include Add _Fork() 2021-08-03 21:19:32 +03:00
kerberos5 pkgbase: Create a FreeBSD-kerberos package 2021-09-07 10:23:14 +02:00
lib libc/locale: Fix races between localeconv(3) and setlocale(3) 2021-09-17 10:47:46 -04:00
libexec Add support for jail.conf.d 2021-09-10 00:30:04 -05:00
release EC2: Default to UEFI booting 2021-09-16 12:23:19 -07:00
rescue Fix building rescue/rescue when sanitizers are enabled 2021-07-06 12:18:30 +01:00
sbin md: Add MD_MUSTDEALLOC support 2021-09-11 20:04:52 +08:00
secure openssh: Add new source files to libssl 2021-09-10 00:56:24 +02:00
share Disable -Woverflow errors for i386 for GCC 9. 2021-09-13 11:00:38 -07:00
stand powerpc64: change CAS to support Radix MMU 2021-09-15 15:24:40 -03:00
sys Eliminate snaplk / bufwait LOR when creating UFS snapshots 2021-09-18 17:02:30 -07:00
targets Fix bootstrapping to actually build lldb-tblgen for later use 2021-08-24 15:04:25 +01:00
tests vfs: Permit unix sockets to be opened with O_PATH 2021-09-17 14:19:06 -04:00
tools nanobsd: Provide empty routines for new embedded scheme 2021-09-16 11:54:18 -06:00
usr.bin calendar.freebsd: Fix off-by-one error 2021-09-17 16:07:23 -07:00
usr.sbin bhyve: Support setting the disk serial number for VirtIO block devices. 2021-09-17 09:55:48 -07:00
.arcconfig Remove history.immutable from .arcconfig 2021-04-13 12:36:25 +01:00
.arclint arc lint: ignore /tests/ in chmod 2017-12-19 03:38:06 +00:00
.cirrus.yml Cirrus-CI: add a manually triggered arm64 task 2021-09-14 15:12:55 -04:00
.clang-format clang-format: Avoid breaking after the opening paren of function definitions 2020-10-28 11:54:00 +00:00
.gitattributes Add a basic clang-format configuration file 2019-06-07 15:23:52 +00:00
.gitignore gitignore: Add .clangd and .ccls-cache 2021-06-04 16:56:08 +08:00
COPYRIGHT copyrights: Happy New Year 2021 2020-12-31 10:29:44 -05:00
LOCKS LOCKS: update current locks 2018-06-09 03:08:04 +00:00
MAINTAINERS [skip ci] volunteer to maintain POSIX AIO 2021-05-30 17:21:12 -06:00
Makefile Revert "Fix native-xtools build" 2021-08-03 10:00:28 -07:00
Makefile.inc1 Fix spelling of BUILDENV_SHELL 2021-09-11 13:27:11 +01:00
Makefile.libcompat Prefer MK_SSP=no to SSP_CFLAGS= 2021-08-04 15:23:22 -03:00
Makefile.sys.inc AUTO_OBJ: For all top-level targets enforce using an OBJDIR. 2017-12-05 21:29:47 +00:00
ObsoleteFiles.inc Don't build and install {llvm,clang,lldb}-tblgen for the target 2021-09-06 09:32:41 +01:00
README.md Whitespace cleanup 2021-03-12 19:57:58 +08:00
RELNOTES RELNOTES: Add entries for KASAN and KMSAN 2021-08-11 13:08:36 -04:00
UPDATING UPDATING: Add entry for commit 55089ef4f8 2021-09-11 15:44:52 -07:00

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